[KevinH]

Interesting ...

FWIW, that stylesheet uses things beyond the css 3.0 spec including @supports like the following:

@supports (height: 100vh) {
  /* Can be used for containers and images 
     but Should be used in combination with .portrait if used for img */
  .h-100 {
    height: 99vh;
    /* Trying to avoid blank page after */
  }
  .h-90 {
    height: 90vh;
  }
  .h-80 {
    height: 80vh;
  }
  .h-70 {
    height: 70vh;
  }
  .h-60 {
    height: 60vh;
  }
  .h-50 {
    height: 50vh;
  }
  .h-40 {
    height: 40vh;
  }
  .h-30 {
    height: 30vh;
  }
  .h-20 {
    height: 20vh;
  }
  .h-10 {
    height: 10vh;
  }
}

@supports is still considered experimental.

I will have to add support for it to the cssparser as it only supports css 3.0.